External ablation of ischemic ventricular tachycardia in an animal infarct model using a scanned proton beam

心肌梗死后的缺血性心肌病患者发生危及生命的室性心律失常的风险很高。全世界每年有超过400万例心脏性猝死，其中大部分是由室性心律失常引起的。近年来，除了植入植入性心律转复/除颤器外，室性心动过速(VT)的导管消融越来越多地被采用。使用射频电流消融心肌中的致心律失常区域。虽然这种方法已经在日常临床实践中得到了应用，但目前只有不超过50%的病例可以长期摆脱室性心动过速。这种有限的成功的一个原因是难以使致心律失常的梗死区的整个室壁内范围均质化。Packer教授等人的初步工作表明，使用放射治疗方法进行心肌消融是可能的。由于其物理性质，质子束特别适合于有针对性的能量应用，同时保护处于危险中的周围器官。因此，质子治疗在放射肿瘤学中的应用越来越多。在这个项目中，我们将研究无导管消融治疗心肌梗死后的室性心动过速，使用质子束治疗。在建立了心肌梗塞后室性心动过速的猪模型后，制定了治疗计划的方法，然后应用了质子束疗法。然后在组织学检查病变之前，通过电生理研究和在完整动物中的多模式成像来分析治疗效果。无导管消融有可能使室性心律失常的临床治疗模式发生转变。

Patients with ischemic cardiomyopathy after myocardial infarction are at high risk for developing life-threatening ventricular arrhythmias. Every year there are over 4 million cases of sudden cardiac death worldwide, most of which are caused by ventricular arrhythmias. In addition to implantation of implantable cardioverters/defibrillators, catheter ablation of ventricular tachycardia (VT) has increasingly been adopted in recent years. Arrhythmogenic areas in the ventricular myocardium are ablated using radio-frequency current. Although being established in everyday clinical practice, this method currently results in long term freedom from VT in no more than 50% of cases. One reason for this limited success lies in the difficulty of homogenizing the arrhythmogenic infarct border zone in its entire intramural extent.Preliminary work by the group of Prof. Packer and others has shown that myocardial ablation is possible using radiotherapeutic approaches. Due to their physical properties, proton beams are particularly suitable for targeted energy application while protecting surrounding organs at risk. Proton therapy is therefore increasingly used in radio-oncology. In this project, we will investigate catheter-free ablation of ventricular tachycardias after myocardial infarction using proton beam therapy in vivo. After developing methods for treatment planning in an established swine model for VT after myocardial infarction, proton beam therapy is applied. Treatment effects are then analyzed by electrophysiological studies and multi-modal imaging in the intact animal before the lesions are examined histologically. Catheter-free ablation has the potential to bring about a paradigm shift in the clinical treatment of ventricular arrhythmia.